Probing top-philic sgluons with LHC Run I data

Many theories beyond the Standard Model predict the existence of colored scalar states, known as sgluons, lying in the adjoint representation of the QCD gauge group. In scenarios where they are top-philic, sgluons are expected to be copiously pair-produced at the LHC via strong interactions with decays into pairs of top quarks or gluons. Consequently, sgluons can be sought in multijet and multitop events at the LHC. We revisit two LHC Run I analyses in which events featuring either the same-sign dileptonic decay of a four-top-quark system or its single leptonic decay are probed. Adopting a simplified model approach, we show how this reinterpretation allows us to extract simultaneous bounds on the sgluon mass and couplings.Comment: 6 pages, 2 figures; v2: some issues in Sec.3.1 clarified, version to appear in PL

Search for same-sign top production at the LHC

An inclusive search for same-sign top-quark pair production in pp collisions at √s = 7TeV is performed using data samples recorded with the ATLAS and CMS detectors at the Large Hadron Collider. These searches are motivated by the hypothesis of Flavor Changing Neutral Currents (FCNC) in the top sector, which would imply enhancement of same-sign top-pair production in pp or p¯p collisions by the exchange of a hypothetical massive Z' boson. As no excess of events is observed, the ATLAS and CMS analyses constrain the FCNC models as a function of the mass the Z' boson and its couplings. The observed limits disfavor the FCNC interpretation of the Tevatron results and limits are set on the cross section of samesign top production at the Large Hadron Collider

Prospectives for stop searches at ATLAS and CMS

The search for supersymmetric partners of the top quark, stop squark, could result in the early discovery of physics beyond the Standard Model at the LHC. We present here the searches for stop squark within the mSUGRA model at ATLAS and CMS detectors. Results of simulation studies are presented. Search for the light stop squark in the low mass SUSY model, originating from the gluino decay, using the final state tb invariant mass at ATLAS is described. Inclusive stop search in the intermediate scenario, using the events with top candidate, leptons and missing energy at CMS is also presented. The discovery prospects in both studies are focused at early data

Queue-length synchronization in a communication networks

We study synchronization in the context of network traffic on a $2-d$ communication network with local clustering and geographic separations. The network consists of nodes and randomly distributed hubs where the top five hubs ranked according to their coefficient of betweenness centrality (CBC) are connected by random assortative and gradient mechanisms. For multiple message traffic, messages can trap at the high CBC hubs, and congestion can build up on the network with long queues at the congested hubs. The queue lengths are seen to synchronize in the congested phase. Both complete and phase synchronization is seen, between pairs of hubs. In the decongested phase, the pairs start clearing, and synchronization is lost. A cascading master-slave relation is seen between the hubs, with the slower hubs (which are slow to decongest) driving the faster ones. These are usually the hubs of high CBC. Similar results are seen for traffic of constant density. Total synchronization between the hubs of high CBC is also seen in the congested regime. Similar behavior is seen for traffic on a network constructed using the Waxman random topology generator. We also demonstrate the existence of phase synchronization in real Internet traffic data.Comment: 13 Pages, 15 figure

Physics Behind Precision

This document provides a writeup of contributions to the FCC-ee mini-workshop on "Physics behind precision" held at CERN, on 2-3 February 2016.Comment: https://indico.cern.ch/event/469561

Prospectives for stop searches at ATLAS and CMS

This talk describes the searches for supersymmetric stop squark within the mSUGRA model at ATLAS and CMS detectors. Results of simulation studies are presented. Search for the light stop squark in the Low Mass SUSY model, originating from the gluino decay, using the final state tb invariant mass at ATLAS is described. Inclusive stop search in the intermediate scenario, using the events with top candidate, leptons and missing energy at CMS is also presented. The discovery prospects with early data in both studies are discussed